问题描述

golang的log模块提供的有写日志功能，示例代码如下：

/* golang log example E-Mail : Mike_Zhang@live.com */ package main import ( "log"
    "os" ) func main() { logFile,err := os.Create("test1.log") defer logFile.Close() if err != nil { log.Fatalln("open file error!") } logger := log.New(logFile,"[Debug]",log.Ldate | log.Ltime | log.LshortfilE) logger.Println("test debug message") logger.SetPrefix("[Info]") logger.Println("test info message") }

运行效果：

[root@local t2]# go build logTest1.go [root@local t2]# ./logTest1 [root@local t2]# cat test1.log [Debug]2017/06/13 23:18:36 logTest1.go:19: test debug message [Info]2017/06/13 23:18:36 logTest1.go:21: test info message [root@local t2]#

go语言的log模块没有提供log rotate接口，但实际开发中我们需要该功能：

我们不希望单个日志过大，否则文本编辑器无法打开，查看比较困难；

更不希望占用太大的存储空间，可以指定最多存多少个日志文件。

解决方案

借助带缓冲的chAnnel来实现。

示例代码如下：

/* golang log rotate example E-Mail : Mike_Zhang@live.com */ package main import ( "fmt"
    "log"
    "os"
    "time" ) const ( BACKUP_COUNT = 5 MAX_FILE_BYTES = 2 * 1024 ) func doRotate(fPrefix String) { for j := BACKUP_COUNT; j >= 1; j-- { curFilename := fmt.Sprintf("%s_%d.log",fPrefix,j) k := j-1 preFilename := fmt.Sprintf("%s_%d.log",k) if k == 0 { preFilename = fmt.Sprintf("%s.log",fPrefiX) } _,err := os.Stat(curFileName) if err == nil { os.Remove(curFileName) fmt.Println("remove : ",curFileName) } _,err = os.Stat(preFileName) if err  == nil { fmt.Println("rename : ",preFilename," => ",curFileName) err = os.Rename(preFilename,curFileName) if err != nil { fmt.Println(err) } } } } func NewLogger(fPrefix String) (*log.Logger,*os.FilE) { var logger *log.Logger filename := fmt.Sprintf("%s.log",fPrefiX) fmt.Println("filename :",fileName) logFile,err := os.OpenFile(filename,os.O_RDWR|os.O_CREATE|os.O_APPEND,0666) if err != nil { fmt.Println("open file error!") } else { logger = log.New(logFile,log.Ldate|log.Ltime|log.LshortfilE) } return logger,logFile } func logWorker(msgQueue <-chan String) { fPrefix := "@H_173_20@msg" logger,logFile := NewLogger(fPrefiX) for msg := range msgQueue { logger.Println(msg) fi,err2 := logFile.Stat() if err2 == nil { if fi.Size() > MAX_FILE_BYTES { logFile.Close() doRotate(fPrefiX) logger,logFile = NewLogger(fPrefiX) } } } logFile.Close() } func main() { msgQueue := make(chan String,1000) go logWorker(msgQueuE) for j := 1; j <= 1000; j++ { msgQueue <- fmt.Sprintf("@H_173_20@msg_%d",j) time.Sleep(1 * time.Second) } close(msgQueuE) return }

运行效果如下：

[root@local t2]# ./logRotateTest1 filename : msg.log rename : msg.log => msg_1.log filename : msg.log rename : msg_1.log => msg_2.log rename : msg.log => msg_1.log filename : msg.log rename : msg_2.log => msg_3.log rename : msg_1.log => msg_2.log rename : msg.log => msg_1.log filename : msg.log ^C